Summary Air Canada Flight 984, a Boeing 767-233 aircraft (registration C-GAUE, serial number 22518) was on a regularly scheduled flight from Toronto/LesterB. Pearson International Airport, Ontario, to Kingston, Jamaica, with seven crew members and 85passengers on board. The aircraft departed from Runway06L in instrument meteorological conditions at 1151eastern standard time. The autopilot was selected ON as the aircraft climbed through approximately 2500feet above sea level (2000feet above ground level). The aircraft then pitched up to 29.5and the airspeed decreased to a near stall condition. The pilot flying (first officer) began to take corrective action as the airspeed decreased through approximately 120knots indicated airspeed (KIAS). As the pitch attitude was being reduced, the stick shaker activated and alerted the pilot not flying (captain) that the aircraft was approaching a stall condition. The captain pushed the control column forward, recovering the aircraft from the near stall condition. The aircraft minimum speed was 109KIAS. Following the occurrence, the flight crew resumed a normal climb profile and proceeded to Jamaica. There were no injuries to the passengers or flight crew. Ce rapport est galement disponible en franais. Other Factual Information Meteorological Information The 12001 aviation routine weather report (METAR) for Toronto/LesterB. Pearson International Airport was as follows: wind from 070True at 17knots, gusting to 22knots; visibility statute mile in light snow; vertical visibility 800feet; temperature -14C; dew point -15C; and altimeter setting30.24. Personnel Information The captain held a valid airline transport pilot licence. He had accumulated over 16000hours of total flight time, of which 3000hours were on Boeing767 aircraft. He was certified and qualified for the flight under existing regulations. He had been awake for four hours and had been performing duties as a flight crew member for two hours prior to the occurrence. The captain was seated in the left seat and was the pilot not flying(PNF). The first officer also held a valid airline transport pilot licence. He had accumulated over 7000hours of total flight time, of which 1000hours were on Boeing767 aircraft. He was certified and qualified for the flight under existing regulations. He had been awake for six hours and had been performing duties as a flight crew member for two hours prior to the occurrence. The first officer was seated in the right seat and was the pilot flying(PF). The captain and the first officer had flown together as a crew on one previous occasion, about six months prior to the occurrence flight. Both flight crew members had been off duty the previous three days. Aircraft Information Records indicate that the aircraft was certified, equipped and maintained in accordance with existing regulations and approved procedures. During the preceding flight, problems were experienced with the left electronic engine control (EEC), and both EECs were turned OFF. When the aircraft arrived in Toronto, the EEC unserviceability was entered in the Defect Log of the Aircraft Journey Log, in accordance with the minimum equipment list. The aircraft was then released for further flights with the EECs turnedON. However, if there was any indication that the EECs were not operating properly, they were to be turned OFF and the engines monitored. The captain was involved in the decisions regarding the EECs. The left EEC was replaced on 28January2004. Following this occurrence, maintenance personnel replaced the left angle-of-attack vane sensor because they suspected that it was faulty and was related to the pitch-up. The removed sensor was inspected and no anomalies were found. Flight Recorders The aircraft was equipped with a Honeywell Universal flight data recorder (FDR), model#980-4100-AXUN. The FDR was removed and downloaded by the operator. A copy of the raw data was sent to the TSB Engineering Laboratory for analysis. AppendixA is a plot of the FDR data from the beginning of the take-off run and shows the pitch up and near stall event. The data shows that, during the occurrence take-off, aircraft rotation started at 148knots indicated airspeed (KIAS) and at 158KIAS the aircraft lifted off. The calculated rotation and take-off safety speeds (VrandV2) were 141and 145KIAS. The aircraft accelerated through 170KIAS about 3seconds after lift-off, and continued to pitch up until a pitch attitude of approximately 16was established. This pitch attitude was maintained and the aircraft continued to accelerate to approximately 185KIAS during the next 20seconds. The vertical speed was approximately 3000feet per minute (fpm) during this time. Approximately 25seconds after lift-off, the pitch attitude began increasing over the next 10seconds from 16to 22. The rate of climb increased to approximately 5100fpm and the airspeed began to decrease. About 30seconds after lift-off the flight director (FD) pitch mode changed from take-off to altitude capture (ALT CAP) mode. Approximately 10seconds later, the centre autopilot was engaged. During this 10-second period (between ALT CAP mode annunciation and autopilot engagement), the airspeed decreased to approximately 160KIAS. After the autopilot was engaged, the aircraft attitude remained at 22up for about 4seconds and then increased to 29.5over the next 10seconds. At the time the autopilot was engaged, the engine pressure ratio (EPR) was decreasing from 1.45(take-off power) to 1.35(climb power). The aircraft maintained 29.5of pitch for about 3seconds before the autopilot was disconnected and the flight crew began a 0.4gpushover to recover from the near stall. The autopilot was engaged for about 17seconds, during which time the airspeed decreased from 160KIAS to 109KIAS. The vane angle of attack reached a maximum value of approximately 13during the pitch-up; this corresponds to a body angle of attack of 17. During the recovery the aircraft pitch attitude reduced to 3nose up. The aircraft descended 300feet during the recovery; the aircraft developed a momentary sink rate before re-establishing a positive rate of climb. Over the next 18to 20seconds, the airspeed increased to 180KIAS and the pitch attitude increased to approximately12. History of the Flight After a normal start and completion of the cockpit checks, the aircraft taxied to the de-icing facility where it was sprayed to remove a trace of ice. The aircraft then taxied to Runway06L for take-off. The flight crew were assigned a departure heading of 065, a slight heading change from the runway heading of 057. In preparation for take-off, the FD, which displays pitch and roll commands on the electronic attitude direction indicator, was in take-off mode and the pitch and roll commands were 8nose-up and wings level, respectively. As the aircraft accelerated through 80KIAS, the FD changed to an air mode and commanded a pitch attitude to maintain an initial climb speed equal to the greater of V22+15, or lift-off speed+15, but limited to V2+25. In this occurrence, the captured speed was V2+25 or 170KIAS. During the initial climb, the FD command bars were commanding a higher-than-normal pitch attitude. Rather than follow the command bars, the PFlimited the pitch of the aircraft to approximately 16nose up initially and then 22. Although the pitch attitude was not increased enough to capture the FD command bars, a high rate of climb (5100fpm) was established during the initial climb after take-off. After take-off, the aircraft heading wandered right to about 076before corrective action was taken to bring the aircraft back to the assigned heading of 065. Climbing through 400feet above ground level (agl), the PFcalled for heading select, which caused the FD roll command to target the heading bug. As the aircraft climbed through 1000 feet agl, the PF called for flight level change (FLCH), climb thrust, command centre3 and bug up4 in accordance with standard operating procedures. When the FLCH was selected, the FDcombined auto-throttle and flight-control computer modes to target the selected altitude, which was set at 5000feet; the target speed was then automatically reset to the current speed of approximately 185KIAS. When the target speed was reset to the current speed, the FD command bars came down to match the current pitch attitude. The flight control computers, using the aircraft's speed and rate of climb, computed that the 5000-foot target altitude was achievable, and the FDswitched to ALT CAP mode and a green ALTCAP was displayed on theFD. The ALTCAP mode denoted a transition manoeuvre entered automatically from the FLCH mode. When climb thrust was selected, engine power was automatically reduced in accordance with a predetermined computer schedule for a more economical climb setting. The FDremained in the ALTCAP mode with the previously calculated capture profile. Normally the time interval between the activation of FLCH, climb thrust, command centre and bug up is the time it takes for the PNF to reach over, press each of the push button switches and select the appropriate speed on the IAS/Mach selector knob, which is about 3to 5seconds total. In this occurrence, at least 10seconds elapsed between the selection of FLCH and centre autopilot engagement. The PFobserved a green ALTCAP indication before the PNFhad selected command centre autopilot. The PFhad never seen the ALTCAP indication this early in the climb profile. The centre autopilot, when engaged, followed the FD in the ALT CAP mode. This resulted in both the airspeed and rate of climb decreasing until the aircraft was no longer able to achieve the ALT CAP profile. When the PNF made the command centre selection, the PF indicated that the FD command bars came down to meet the airplane symbol, which was pitched up 22. After concluding that the autopilot was functioning and flying the aircraft, the PF focussed his attention on the engine gauges to ensure that climb thrust was maintained. When he returned his scan to the electronic attitude direction indicator, he noted that the FD command bars had disappeared and he alerted the PNF. He also noted that the green ALT CAP indication had turned amber.5 This amber light indicated a "degraded operating condition" in that the aircraft was no longer able to achieve the ALT CAP profile. Some manner of intervention by the flight crew would be required to rectify the situation, including, but not limited to, disengaging the autopilot and manually flying the aircraft. In this occurrence, neither pilot intervened, and the autopilot was not disengaged. By the time the PNF looked at the PF's electronic attitude direction indicator, the FDcommand bars had reappeared, and he observed a normal display. However, he reset the FD to confirm its operation and then continued with other PNF duties. Resetting the FD had no effect on its operation other than to refresh the display screen. Observing the return of the FD command bars, the PFreturned his attention to the engine gauges. Moments later, he noted that the aircraft had pitched up to about 30, observed the airspeed decreasing through 140KIAS, and at 111KIAS he deactivated the autopilot and began to push the control yoke forward. The stick shaker then activated, prompting the PNF to aggressively push the control yoke forward. There are several versions of the flight-control computer software in use on Boeing767 aircraft. The Air Canada fleet uses two different versions of the software. C-GAUE was equipped with customer option3, which, in the event of an excessive angle of attack, provides passive stall protection in the form of a Level B caution. This protection consists of the following aural and visual warnings: the FDcommand bars are hidden from view, the ALTCAP indication changes to amber, the amber autopilot light illuminates, a master caution light illuminates and an aural warning sounds. Other aircraft in the Air Canada Boeing767 fleet are equipped with customer option6, which also includes active speed protection; there are options, other than 3and 6,that are available. For aircraft equipped with the option 6flight control law upgrade, the FDcommand bars will automatically come down to direct the pilot or autopilot to decrease the pitch if the airspeed decreases below the selected speed (5knots below the selected speed if the autothrottle is engaged).